Heney millee



(No Model.)

H. MILLER.

IGRATE BAR. No. 253,220. Patented Feb. 7,1882.

WITNESSES; INVENTORI HENRY MILLER, OF PROVIDENCE, RHODE ISLAND.

GRATE-BAR.

SPECIFICATION forming part of Letters Patent No. 253,220, dated February 7, 1882.

Application filed Maroh26,1881. (No model.)

To all whom it may concern:

Be it known that I, HENRY MiLLER, of the city and county of Providence, and State of Rhode Island, have invented a new and useful Improvement in Grate-Bars; and I hereby declare that the following is a full, clear, and exact description of the same, reference being bad to the accompanying drawings, forming part of this specification.

This invention has reference to an improvement in the construction ofgrate-bars, in which series oflight bars are made to support the fuel, cast in one piece with a supportingbar, which is placed below the direct action of the fire, as will be more fully set forth hereinafter.

The uses of a grate are to support the fuel, allow the ashes to fall to the ash-pit, and to supply the air to the fuel. The support of the fuel requires a strong and firm grate, whereas the admission of air and the discharge of the ashes requires an open grating. forming the least possible obstruction. To secure these desirable qualities light open grates have been placed upon strong bearing-bars; but such light grates are liable to be displaced when, in large furnaces, the slicing or cleaning bars are forced over the grate to remove ashes and clinkers. To avoid this difficulty and retain the advantages, I cast the light open grate in one piece with the bearing-bars, and of such form and so connected therewith that the parts will be securely held together, and warping and breaking from uneven expansions and contractions prevented.

Figure l is a side view of my improved gratebar. Fig. 2 is a top view of the grate formed of such bars. Fig. 3 is an end view of one bar. Fig. 4 is a sectional view of the same.

In the drawings, a is the main bearing-bar, provided on each end with the projecting lips I), so as to retain the bars on the cross-bearers on which they are supported.

0 o are short bars made in sets of three the central one being united integrallyi'or a short distance at the center of its length with the main bearing-bar, and the two outside bars 0 0 being supported by the bracketsd cl near the center of their length, the ends being left free to expand and contract. The whole bar is cast in one piece, so that the short bars cannot be displaced.

The object in connecting the central top bar for a portion of its length with the main supporting-bar is to relieve the brackets of lateral strain from the expansion of the top bars when a fire is first kindled, and which would be liable to break said brackets, as well as to warp or break the top bars.

Two sets of bars are used in a furnace, so that the ends of one set of the short bars 0 c on one bar will be opposite the center of the short bars on the two adjoining bars, and the slice-bar, in cleaning the tire, will not be liable to strike against the ends of the bars 0 0, but will be supported by the adjoining bars.

The short bars, which are soonest affected by the fire, are free except at the junction of the central short bar with the supporting-bar, and this integral junction communicates sufficient heat to the parts of the supporting-bar adjacent thereto to cause them to so expand as not to interfere with the expansion of said central short bar. As the outside short bars are carried by the central short bar they are all-free to expand together. When the grate is cooling off the short bars cool the most rapidly, but the integral junction withdraws sufficient heat from the adjacent portions of the supporting-bar to somewhat retard the cooling of the short bars, while at the same time hastening the cooling of the supporting-bar, so that such an equalization of contraction is secured as to obviate breakage or warping.

Having thus described my invention, Iclaim as new anddesire to secure by Letters Patent- 1 The combination, with the supporting-bar a, of the short bars 0 o c, the central one ofwhich is connected integrally for an intermediate portion of its length with said supporting-bar, the said short bars being connected laterally by the brackets d, substantially as described.

In witness whereof I have hereunto affixed my name.

WM. L. Goor, J. A. MILLER, Jr. 

